Agata’s composure shattered as if he’d struck her. ‘I couldn’t do it,’ she confessed. She started humming and shivering. ‘I wasn’t strong enough.’

Ramiro was horrified. ‘It’s all right, calm down! I was just asking.’ In all their time together he’d never seen her so wretched. ‘No one else could break the innovation block – and so far you’ve had about three bells without it.’

‘You don’t understand,’ she said. ‘I already had a plan three stints ago – no innovations, it was all gleaned from textbooks. But I couldn’t go through with it.’

Ramiro led her over to the couch and sat beside her. ‘What happened?’ he asked gently.

Agata explained between bouts of shivering. ‘I had everything worked out so that Celia would think I’d done a final shift and then quit. No one would have been searching the tunnels for my body. I’d even found a way to repair the grilles behind me so that the other workers wouldn’t notice the damage. I was going to schedule a message to you and Tarquinia, telling you the threshold that the refractive index of the air near the axis would need to cross for you to know that you could cancel the bombs. But after I sent a message to myself to hold fast against Giacomo, I lost all my courage.’

Ramiro squeezed her shoulder. ‘I’m glad you didn’t do it.’

‘Why?’ she asked miserably. ‘If your own plan’s gone bad, all that’s left to explain the disruption is a meteor—’

‘We’re not there yet,’ he protested. He described what had happened to the occulter, and Tarquinia’s scheme to get out and fix it. ‘But if you have any non-suicidal alternatives, don’t keep them to yourself.’ Ramiro suspected that the three of them working together might have found a way to get Agata’s chemical into the cooling chamber, but it was too late for that now.

‘I have no more ideas,’ Agata said forlornly. ‘That’s why I asked Serena and Gineto for the books. The Council has all of Medoro’s notes on the time-reversed camera, but his design didn’t come out of nowhere. If I can retrace the steps of his education myself, there’s a chance I might see something that I missed.’

Ramiro pictured the bulging container she’d been lugging down the corridor; he couldn’t read that much in a year. But if Tarquinia couldn’t repair the occulter, they’d have three days to mine Medoro’s textbooks and come up with a new way to shut down the system.

‘I shouldn’t keep you from your study, then,’ he said. ‘Just promise me you won’t try anything like the last plan.’